Optically active hydroxyesters and five-membered ring lactones have been noted as important intermediates for synthesizing various medicines, agricultural chemicals, and biologically active substances.
Especially optically active (R)-4-hydroxy-tetradecynoates, one of (R)-4-hydroxyesters (formula 1), and optically active (R)-5-(1-decynyl)-oxacyclopentan-2-one, of (R)-five-membered ring lactones (formula 5), are important intermediates for synthesizing pheromone of Popillia japonica Newman (see Shuji Senda and Kenji Mori, Agrical. Biol. Chem., 47 (11) 2595 to 2598 (1983)). ##STR2##
Here, R.sub.1 denotes --C.tbd.C--R.sub.3 or --C.dbd.C--R.sub.3 ; R.sub.2 and R.sub.3 denote straight chain or branched alkyl groups containing 1 to 10 carbon atoms; * denotes asymmetric carbon atoms.
Optically active (R)-4-hydroxyesters (formula 1) and optically active (R)-membered ring lactones (formula 5) are interconvertible.
Optically active (R)-4-hydroxyesters are lactonized to optically active (R)-five-membered ring lactones in the usual way.
On the other hand, optically active (R)-five-membered ring lactones are hydrolyzed and esterified to optically active (R)-4-hydroxyesters.
The activity of the pheromone of Popillia jaonica Newman, (R,Z)-(-)-5-(1-decenyl)-dihydro-2-(3H)-furanone, is drastically reduced in the presence of its (S,Z)-isomer.
It is said that existence of 0.5% (S,Z)-isomer lowers the activity of the pheromone to 60%, 2% (S,Z)-isomer to one third, and 6% (S.Z)-isomer to zero.
It is accordingly very important to produce, in a high state of purity, (R)-4-hydroxy-5-tetradecynoates and (R)-5-(1-decinyl)-oxacyclopentan-2-one.
However, no efficient producing and purifying process has been provided so far.